Gisle

Gisle (died 1204) was a Norwegian noble who was affiliated with the Birkebeiners during the Norwegian Civil War. He had an affair with Sverre of Norway's widow Margaret of Sweden, whom he convinced to poison King Haakon III of Norway - her stepson - in 1204, predicting that the Baglers would ultimately defeat their faction. He covered up his treason by having Inge Bardsson imprisoned, claiming that he had the most to benefit from Haakon's death. Gisle then falsely claimed that the infant Haakon IV of Norway had died in the freezing winter, and that he would accept the task of becoming King of Norway; he then had an affair with Margaret's daughter Christina of Norway, and he intended to marry her. However, their wedding was interrupted when Torstein and Inge arrived, and Inge had Gisle taken away to be executed for treason, while he became the new King.